Yoke-type compressor

ABSTRACT

A hermetic motor-compressor assembly includes a spring-mounted rigidly interconnected motor and compressor in a sealed container. The compressor is of the four cylinder direct-driven Scotch yoke type, with two pairs of cylinders at right angles on horizontal axes, the pistons of opposed cylinders being paired by means of a rigid combined yoke and dual connecting rod assembly. The yokes are actuated by rectangular slide blocks fitted on a common crank throw and the yokes and blocks are keyed against displacement with respect to the axes of the cylinders.

United States Patent [191 Rogers et a].

[ June 11, 1974 YOKE-TYPE COMPRESSOR [75] Inventors: Robert E. Rogers; George F. Davis,

Jr., both of Sidney, Ohio [73] Assignee: Copeland Corporations, Sidney,

Ohio

22 Filed: July 17, 1973 [21 Appl. No.3 380,002

I Related US. Application Data [63] Continuation of Ser. No. 207,841, Dec. 14, I971,

abandoned,

[52] US. Cl 417/536, 74/50, 92/74 [51] Int. Cl. F04b 27/02 [58] Field of Search 74/50; 92/74; 417/536, 417/273 [56] References Cited UNITED STATES PATENTS 1,343,407 6/l920 Rottel 74/50 2/1954 Browne ..4l7/536 6/l97l Gannaway ..92/74X Primary Examiner-C. J. Husar Assistant ExaminerLeonard Smith Attorney, Agent, or Firml-larness, Dickey & Pierce [5 7] ABSTRACT 2 Claims, 5 Drawing Figures amsioas PHENTEDM 1 1 m4 I saw 2 OF 3 YOKE-TYPE COMPRESSOR This is a continuation, of application Ser. No. 207,847, filed Dec. 14, 1971, now abandoned.

BACKGROUND OF THE INVENTION In the refrigeration field it is usually desired that compressor operation be as quiet as possible. Difficulty has been encountered in the elimination of noise from multicylinder yoke-type refrigeration compressors having a plurality of yokes grouped on a single crankshaft. The present invention has as its overall objective the provision of improved extremely simple means for reducing the noise caused by the operation of such compressors. The principles of the invention are nevertheless applicable to other rotary machines such as motors incorporating similar driving mechanisms, and references in this specification and the following claims to compressors are intended to encompass such other machines.

BRIEF DESCRIPTION OF THE FIGURES OF DRAWING FIG. 1 is a vertical diametric sectional elevational view of a refrigeration motor-compressor of the hermetic type, incorporating a preferred form of the invention;

FIG. 2 is a cross section taken substantially on the line IIII of FIG. 1, and looking in the direction of the arrows;

FIG. 3 is a fragmentary sectional view of the compressor body with other parts omitted, taken substantially as indicated by the line and arrows IIIIII on FIG. 2;

FIG. 4 is a fragmentary elevational view of the body, with other parts removed, taken substantially as indicated by the line and arrows IVIV on FIG. 1; and

FIG. 5 is a sectional detail taken substantially on the line V-V of FIG. 1, and looking in the direction of the arrows.

DETAILED DESCRIPTION OF THE PREFERRED FORM OF THE INVENTION Reference character designates generally the welded casing of a refrigeration motor-compressor containing in its upper portion, on a vertical axis, an induction-type electric motor generally designated 12, the armature shaft 14 of which projects downwardly from the electric motor and is formed with an integral vestigal crankshaft portion 15 having a single throw 16 which is of sufficient axial length to accommodate two Scotch yokes 20, 21 mounted close together thereon in horizontal planes and moving in paths perpendicular to each other.

The compressor body 22 is formed as a rigid casting bored transversely to provide two pairs of coaxial cylinders, one pair, comprising cylinders 24, 25, being aligned with the upper yoke and having pistons 26, 27 rigidly connected to the yoke 20 by colinear connecting rod portions 28, 29, while the cylinders 30, 31 of the other pair, upon an axis perpendicular to the axis of cylinders 24, 25, have their pistons 32, 33 similarly connected to and aligned with the lower yoke 21.

The compressor body 22 is provided with an integral upwardly extending open-topped cylindrical support portion 34 in which the stator 36 of the motor is fitted and supported. The support portion 34 is also provided with radial ears 38 which carry horizontally arranged helical compression springs 40 coacting with brackets 42 secured to the interior of the casing 10 to absorb torsional forces.

A web section 45 of the body 22 positioned between the motor and compressor sections carries a central bearing neck 46 for the shaft. A bottom discharge cover 50 secured to the body by machine screws as 52 incorporates a bottom bearing 54 for the shaft and also includes discharge chamber areas 55 communicating with coacting discharge cavity portions as 56 in the body, such portions being proportioned to provide muffling action.

A downwardly opening concentric annular recess 60 formed in the discharge cover 50 accommodates and positions a helico-spiral compression spring 62 which supports the motor-compressor assembly vertically as well as resisting lateral forces.

In the preferred construction shown, suction gas is delivered to the interior of the compressor via a fitting 65. A sheet metal partitioning sleeve 66 is fitted around the upper portion of the stator 36 of the motor and connected in sealed relation to the upper extremity of the supporting portion 34 of the compressor body. The sleeve 66 has an inwardly projecting flange 67 at its upper end bounding a relatively large central opening 68 leading into the interior of the sleeve 66 from the upper interior of the casing. A dished shield and spring locating member 70 overlies the opening 68 and is secured as by tack welds, designated 72, to the flange 67, the principal area of the overlying flange portion 74 of the member 70 being spaced above the flange 67, thereby providing an annular horizontal entrance opening 75 for the suction gas between the flanges 67, 74. The flange 67 is defined by a depressed top portion of the shielding sleeve 66 so that the entrance 75 is surrounded by an annular upwardly bulged bead 76. Oil and/or liquid refrigerant which may be entrained with the returning suction gas tends to fall to the oil sump area at the bottom of the casing, but if any droplets are carried upwardly and radially inwardly toward the entrance 75, their inertia will be such that they are guided away from the entrance by the bulge 76 so that as a practical matter only dry gas finds its way into the space within the sleeve 66.

The sleeve 66 is somewhat outspaced from the stator 36, so that the space within the sleeve around the motor communicates with channels 77 formed in the inner wall of the supporting portion 34 of the body and extending downwardly from its top to the space 78 below the stator inside the support portion 34. The support portion 34 and sleeve 66 are impervious, and the downflowing gas travels not only through the space around the stator, but also through the space between the stator and the armature, and through additional passages as 80 in the armature. A perforated baffle plate 79 in support portion 34 and spaced above web 45 creates a muffling chamber 81. Vertical passages 82 in the body 22 have their tops open in the upper surface of web 45 and conduct the gas via communicating horizontal passages 83 to the suction spaces 87 in the cylinder heads. Ring-type suction valves admit gas to the cylinders on the suction strokes, and centrally positioned discharge valves 88 admit the compressed gas to head compression chambers 90 which communicate via passages 92 with the discharge muffling chamber 56, from which it is conducted via mufflering chamber portions 55 to the discharge tube 95 leading to the discharge fitting 96 on the exterior of the casing.

Each of the yokes 20, 21 is actuated by a rectangular slide block 100, 101. The slide blocks are journaled on the throw l6, and are slightly spaced from each other therealong, and from the cheeks 17, 19 of the crankshaft. It will be appreciated that some vertical movement of the shaft occurs during operation of the compressor, and that the yokes are held against any substantial vertical movement by the pistons. Since the yokes are arranged, and move, perpendicularly to each other, and are close together, each yoke, because of its engagement with its slideblock, is inherently capable of preventing the other from rocking unduly, or to an obstructing or interfering position, around the axis of its pair of cylinders. In other words, if the yokes were not close together, each one could rock around the longitudinal axis of its cylinders, but in no other plane. When they are close together, however, each yoke has the inherent ability to restrain the other in this regard. We have nevertheless found in the course of repeated testing that even if the slideblocks, yokes and other parts are fitted or held by tolerances as close as practical, considerable previously unexplained and undesirable noise occurs during operation of such compressors when constructed in accordance with previous practice. Although we cannot be certain as to the cause, and are not aware of a force which would cause such rocking, we believe that this noise is due at least partly to rocking of the yokes around the cylinder axis. We have also found by experiment that by the provision of an additional restraining means in the form of a key or guide for each yoke, which holds each yoke and slideblock against any angular or lateral displacement, the noise is greatly reduced.

In the preferred construction shown, each connecting rod portion is integral with its piston, and an axial hole 102 is drilled through the piston and connecting rod to receive a screw 104 which secures the piston and connecting rod to the yoke, as shown in FIG. 1. The slideblock is prevented by the crank throw from rocking around the cylinder axis, and a keying or guide portion comprising a U-shaped sheet metal member 105 is secured to the yoke and is provided with flat side arm portions 106, 107 overlying the yoke and the block and preventing any relative angular or lateral displacement of the yoke and block during their relative sliding movement. In the construction shown, the U-shaped keying member 105 has its bight portion clamped between the yoke and the connecting rod, where it is held when the screw 104 is tightened, as is also clearly shown in FIG. 1. Two of the keying devices 105 are provided for each yoke, one clamped to each connecting rod, so that movement of the parts in any plane in a manner which could result in noise-making contact is effectively prevented. As shown in FIG. 1, the side portions 106, 107 of each keying device extend the effective length of slide block travel.

The Detailed Description of the Preferred Form of the Invention, and the accompanying drawings, have been furnished in compliance with the statutory requirement to set forth the best mode contemplated by the inventors of carrying out the invention. The prior portions consisting of the Abstract of the Disclosure" and the Background of the Invention are furnished without prejudice to comply with administrativerequirements of the Patent Office.

What is claimed is:

1. In a compressor or the like of the type having a crankshaft including a throw, a plurality of slide members journaled closely adjacent one another on said throw, and a plurality of yokes, each slide member being slidably interengaged with one only of the yokes, said yokes being arranged in parallel planes but at angles to one another, the novelty which comprises means including a plurality of guiding means, at least one such guiding means slidably interconnecting each slide member and its yoke and preventing unwanted changes of alignment thereof to an extent which would permit contact between the yokes, or between the slide members, throughout the travel of the slide members, each guide means comprising at least two sheet metal portions secured to each yoke, said portions overhanging both sides of the yoke and both sides of the slide member which is interengaged with such yoke.

2. In a compressor or the like having a plurality of pairs of opposed coaxial cylinders, a yoke interposed between the cylinders of each pair and a piston in each cylinder, the opposed pistons of each pair being rigidly connected to the interposed yoke, a common crank throw extending through at least two of said yokes, a slideblock in each yoke, the slideblocks being journaled on said throw, and guide portions secured with respect to the yokes and slidably interengaged with opposed lateral portions of the slideblocks, said guide portions and the lateral portions of the slideblocks being perpendicular to the axis of the throw whereby the yokes are prevented from rocking into engagement with each other by turning around the axes of the cylinders, the guide portions comprising a sheet metal member of U-channel form secured to each yoke and overhanging both sides of the yoke and both sides of the slideblock. 

1. In a compressor or the like of the type having a crankshaft including a throw, a plurality of slide members journaled closely adjacent one another on said throw, and a plurality of yokes, each slide member being slidably interengaged with one only of the yokes, said yokes being arranged in parallel planes but at angles to one another, the novelty which comprises means including a plurality of guiding means, at least one such guiding means slidably interconnecting each slide member and its yoke and preventing unwanted changes of alignment thereof to an extent which would permit contact between the yokes, or between the slide members, throughout the travel of the slide members, each guide means comprising at least two sheet metal portions secured to each yoke, said portions overhanging both sides of the yoke and both sides of the slide member which is interengaged with such yoke.
 2. In a compressor or the like having a plurality of pairs of opposed coaxial cylinders, a yoke interposed between the cylinders of each pair and a piston in each cylinder, the opposed pistons of each pair being rigidly connected to the interposed yoke, a common crank throw extending through at least two of said yokes, a slideblock in each yoke, the slideblocks being journaled on said throw, and guide portions secured with respect to the yokes and slidably interengaged with opposed lateral portions of the slideblocks, said guide portions and the lateral portions of the slideblocks being perpendicular to the axis of the throw whereby the yokes are prevented from rocking into engagement with each other by turning around the axes of the cylinders, the guide portions comprising a sheet metal member of U-channel form secured to each yoke and overhanging both sides of the yoke and both sides of the slideblock. 